Many chemical processes involve the reaction of a combustible material with an oxidant. Within proper design constraints and operating conditions, these reactions can take place safely. However, if there is an upset in one or more of the operating conditions or a misapplication of the process, it is possible that the materials within the process can be within explosive or detonable concentration limits.
Microchannel reactors have the ability to handle gas mixtures that could detonate in conventional apparatus. In order to safely handle these mixtures, the common understanding has been to use very small diameter microchannels that are below the quench gap for the selected, potentially explosive, gas mixture. Hagendorf et al. recommend limiting the total reactor volume to approximately 1 cm3 to avoid the potential for detonation. See Hagendorf, U., M. Janicke, and F. Schüth, 1998, “A Pt/Al2O3 Coated Microstructured Reactor/Heat Exchanger for the Controlled H2/O2-Reaction in the Explosion Regime,” Process Miniaturization: 2nd International Conference on Microreaction Technology, New Orleans, La. March 9-12, published by the American Institute of Chemical Engineers, New York, N.Y. Other workers have explained that flammable gas mixtures such as ethylene and oxygen should be handled safely by requiring that the channel gap be less than the quench distance (also referred to as quench gap in this invention). See Kestenbaum, H., Al Lange de Oliveira, W. Schmidt, F. Schüth, W. Ehrfeld, K. Gebauer, H. Löwe, Th. Richter, 2000, “Sythesis of ethylene oxide in a microreaction system,” Microreaction Technology: Industrial Prospectus, IMRET 3: Proceedings of the Third International Conference on Microreaction Technology, W. Ehrfeld (Ed.), Springer-Verlag; Haas-Santo, K., O. Görke, K. Schubert, J. Fiedler, and H. Funke, 2001, “A Microstructure Reactor System for the Controlled Oxidation of Hydrogen for possible Application in Space,” Microreaction Technology, IMRET 5: Proceedings of the Third International Conference on Microreaction Technology, W. Matlosz et al. (Eds.), Springer-Verlag.